The naturally occurring prostaglandin E2 (PGE2) is known in medicine as dinoprostone, and it is the most common and most biologically active of the mammalian prostaglandins. It has important effects during labour and also stimulates osteoblasts to release factors which stimulate bone resorption by osteoclasts (a type of bone cell that removes bone tissue by removing the bone's mineralized matrix). PGE2 is also the prostaglandin that ultimately induces fever. PGE2 has been shown to increase vasodilation and cAMP production, enhance the effects of bradykinin and histamine, and induce uterine contractions and platelet aggregation. PGE2 is also responsible for maintaining the open passageway of the fetal ductus arteriosus, decreasing T-cell proliferation and lymphocyte migration, and activating the secretion of IL-1α and IL-2. PGE2 exhibits both pro- and anti-inflammatory effects, particularly on dendritic cells (DC). Depending on the nature of maturation signals, PGE2 has different and sometimes opposite effects on DC biology. PGE2 exerts an inhibitory action, reducing the maturation of DC and their ability to present antigen. PGE2 has also been shown to stimulate DC and promote IL-12 production when given in combination with TNF-alpha. PGE2 is an environmentally bioactive substance. Its action is prolonged and sustained by other factors especially IL-10. It modulates the activities of professional DC by acting on their differentiation, maturation, and their ability to secrete cytokines. PGE2 is a potent inducer of IL-10 in bone marrow-derived DC (BM-DC). PGE2-induced IL-10 is a key regulator of the BM-DC pro-inflammatory phenotype (PMID: 16978535 ). Prostaglandins are eicosanoids. The eicosanoids consist of the prostaglandins (PGs), thromboxanes (TXs), leukotrienes (LTs), and lipoxins (LXs). The PGs and TXs are collectively identified as prostanoids. Prostaglandins were originally shown to be synthesized in the prostate gland, thromboxanes from platelets (thrombocytes), and leukotrienes from leukocytes, hence the derivation of their names. All mammalian cells except erythrocytes synthesize eicosanoids. These molecules are extremely potent and are able to cause profound physiological effects at very dilute concentrations. All eicosanoids function locally at the site of synthesis through receptor-mediated G-protein linked signalling pathways.

This compound belongs to the class of organic compounds known as prostaglandins and related compounds. These are unsaturated carboxylic acids consisting of a 20 carbon skeleton that also contains a five member ring, and are based upon the fatty acid arachidonic acid.

Enzymes

NADPH-dependent reductase with broad substrate specificity. Catalyzes the reduction of a wide variety of carbonyl compounds including quinones, prostaglandins, menadione, plus various xenobiotics. Catalyzes the reduction of the antitumor anthracyclines doxorubicin and daunorubicin to the cardiotoxic compounds doxorubicinol and daunorubicinol. Can convert prostaglandin E2 to prostaglandin F2-alpha. Can bind glutathione, which explains its higher affinity for glutathione-conjugated substrates. Catalyzes the reduction of S-nitrosoglutathione.

Prostaglandin inactivation. Contributes to the regulation of events that are under the control of prostaglandin levels. Catalyzes the NAD-dependent dehydrogenation of lipoxin A4 to form 15-oxo-lipoxin A4. Inhibits in vivo proliferation of colon cancer cells.

Reactions

Receptor for prostaglandin E2 (PGE2). The activity of this receptor is mediated by G(q) proteins which activate a phosphatidylinositol-calcium second messenger system. May play a role as an important modulator of renal function. Implicated the smooth muscle contractile response to PGE2 in various tissues

Receptor for prostaglandin E2 (PGE2). The activity of this receptor is mediated by G(s) proteins that stimulate adenylate cyclase. Has a relaxing effect on smooth muscle. May play an important role in regulating renal hemodynamics, intestinal epithelial transport, adrenal aldosterone secretion, and uterine function

Isomerase that catalyzes the conversion of unstable intermediate of prostaglandin E2 H2 (PGH2) into the more stable prostaglandin E2 (PGE2) form. May also have transactivation activity toward IFN-gamma (IFNG), possibly via an interaction with CEBPB; however, the relevance of transcription activation activity remains unclear.

Reactions

Receptor for prostaglandin E2 (PGE2); the EP3 receptor may be involved in inhibition of gastric acid secretion, modulation of neurotransmitter release in central and peripheral neurons, inhibition of sodium and water reabsorption in kidney tubulus and contraction in uterine smooth muscle. The activity of this receptor can couple to both the inhibition of adenylate cyclase mediated by G-I proteins, and to an elevation of intracellular calcium. The various isoforms have identical ligand binding properties but can interact with different second messenger systems

Receptor for prostaglandin E2 (PGE2). The activity of this receptor is mediated by G(s) proteins that stimulate adenylate cyclase. The subsequent raise in intracellular cAMP is responsible for the relaxing effect of this receptor on smooth muscle

Reactions

Transporters

Mediates the Na(+)-independent transport of organic anions such as pravastatin, taurocholate, methotrexate, dehydroepiandrosterone sulfate, 17-beta-glucuronosyl estradiol, estrone sulfate, prostaglandin E2, thromboxane B2, leukotriene C3, leukotriene E4, thyroxine and triiodothyronine. May play an important role in the clearance of bile acids and organic anions from the liver